Thermal energy generation

ABSTRACT

Impure water is continuously sprayed into an elongated conduit having an inlet for the water adjacent one end and an open outlet remote from the inlet while maintaining the inner surface of the conduit at a temperature such that the water not only is flashed into steam but also is substantially immediately converted into superheated steam under the confinement imposed by the inner surface of the conduit with concomitant pressure build-up which propels the steam and superheated steam toward the outlet with a velocity at which the conduit is self-scavenging in that there is no deposit on or attack on the inner surface of said conduit and said inner surfaces remain clean notwithstanding indefinitely long periods of continuous operation.

United States Patent 1191 Ross [ THERMAL ENERGY GENERATION [75] Inventor: Sigmund Lance Ross, New York,

Assigneei (lscar Shufiman, ScarsdaleTNY.

22 Filed: Nov. 26, 1971 21 Appl.No.: 202,215

52 US. Cl. ...122/4,s7, 122/31 R 1451 Apr. 17, 1973 Primary ExaminerKenneth W. Sprague AtzorneyRichard K. Parsell ABSTRACT Impure water is continuously sprayed into an elongated conduit having an inlet for the water adjacent one end and an open outlet remote from the inlet while maintaining the inner surface of the conduit at a temperature such that the water not only is flashed into steam but also is substantially immediately con verted into superheated steam under the confinement imposed by the inner surface of the conduit with concomitant pressure build-up which propels the steam and superheated steam toward the outlet 7 with a velocity at which the conduit is self-scavenging in that there is no deposit on or attack on the inner surface of said conduit and said inner surfaces remain clean notwithstanding indefinitely long periods of continuous operation.

17 Claims, 12 Drawing Figures PATENTEDAPRITW 3.727. 588

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SHEET 2 OF 5 Q III pllll HOT GASES INVENTOR SIGHUIID LANCE R0! PATENTEMPRI719173 3.727. 588

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sum 5 OF 5 BLEED --OFF OF HOT GASES STEAM sum LEGEND EN\TRAINED MINERALS 73 p-msnuuuaous rusmne or main worms INVENTOR N V SIGNUND LANCE ROSS BY I SUPERHEATER THERMAL ENERGY GENERATION FIELD OF INVENTION This invention relates to the conversion of heat energy into steam and relates more especially to method and means for the continuous production of superheated steam from impure water.

BACKGROUND OF INVENTION Natural waters usually contain certain dissolved salts and chemical and biological gases together with other organic and inorganic substances. The dissolved salts are chiefly carbonates, sulfates and chlorides of calcium, sodium and magnesium as well as occasionally iron, aluminum and silicon. The dissolved gases are oxygen and carbon dioxide. The water may contain organic material such as tiny flora or fauna. Other contaminants also may be present such as those resulting from sewage and industrial wastes. For the sake of brevity, water containing one or more of the aforesaid contaminating substances is referred to herein and in the claims as impure water and the contaminating sub stances are referred to as impurities.

When impurities such as those mentioned above occur in water that is used in a boiler feed they are highly disadvantageous in that they variously result in scaling, foaming; corrosion, priming and embrittlement. Moreover, to the extent that additional water is added to make up for steam losses, the additional impurities keep on accumulating. In order to minimize such accumulation, it is common practice to use the steam boiler in a closed system whereby water resulting from the condensation of the generated steam is returned to the boiler usually after de-aeration and to pretreat such small amount of fresh boiler feed water as may be added to remove impurities therefrom. If these precautions are not taken the aforesaid'difficulties are encountered and, while it is possible to resort from time to time to expedients such as chemical treatment and/or boiler water blow-down, they fall far short of permitting the use of ordinary impure water as boiler feed in a practical operational system. In the generation of superheated steam special care has to be taken as regards the purity of the water employed and it is com-1 mon practice for such purpose to employ triple distilled water. However, this is expensive and troublesome and becomes highly impractical if superheated steam is to be used in an open system under conditions such that none of the condensate is returned to the boiler. Such an open system for the generation of steam or superheated steam is of advantage undercertain conditions as, for example, in oil recovery operations wherein steam or superheated steam is employed in the stimulation of oil wells. However, notwithstanding the occurrence of large amounts of water on the site, such water is highly saline and it has been considered necessary to bring in the make-up water in tank trucks even though the drilling site may be far removed from a source of pure water.

In the case ofa highly saline water such as sea water, to the best of my knowledge it has been regarded as a technological impossibility to employ such water as a practical source of boiler feed water for the generation of steam. The same is true of the saline water that usually is encountered in oil fields.

OBJECTS OF THE INVENTION A principal object and feature of this invention is that of providing method and apparatus for the production of superheated steam continuously over an indefinitely long period of time utilizing impure water.

It is a further object and feature of this invention to provide method and means for the: production of superheated steam from impure water without scaling, corrosion or other injury to the heating surfaces or to other instrumentalities.

A further object and feature of this invention is that of providing method and apparatus having a large capacitor for the generation of superheated steam in relation to the size of the unit that is used for doing so.

It is a further object and feature of the invention to provide method and means for generating steam which eliminates the necessity for purifying, dioxidizing, or demineralizing the feed water.

It is a further object and feature of this invention to provide an open system for generating superheated steam from impure water.

GENERAL STATEMENT OF THE INVENTION According to this invention, impure water is continuously sprayed by means of a spray nozzle configuration or device into an elongated conduit having an inlet for the water adjacent one end and an. open outlet remote from said inlet and the inner surface of which is maintained at a temperature such that the water not only is flashed into steam continuously and virtually instantaneously but also is rapidly converted into superheated steam under the confinement imposed by the inner surface of the conduit with concomitant pressure build-up which propels the superheated steam at high velocity toward the outlet. I have found that under these conditions of operation the superheated steam can be caused to attain a velocity at which the inner surface of the conduit becomes self-scavenging in that the impurities which normally would tend to form scale or other deposits or cause corrosion attain such buoyancy that notwithstanding their presence the inner surface of the conduit remains clean and undamaged and the generation of steam can be continued for an indefinitely long period of continuous operation in an open system wherein the generated superheated steam merely is applied to its intended use and dissipated, as distinguished from a closed system wherein the steam is condensed and the condensate is usedfor boiler feed.

The instantaneous flashing or the injected spray of water is promoted by causing it to be injected so that its direction is substantially in alignment with the axis of the elongated conduit and by causing the conduit to be substantially linear in the region ofthe spray. The spray preferably is directed so that the water particles are projected in the form ofa cone wherein the direction of projection of the outermost particles is at an angle of only l or 2 with respect to the inner surface of the conduit. If this angle is greater than about 4 it is more difficult to prevent the formation of a deposit on the inner surface of the conduit. While the foregoing is preferred practice, the spray can be accomplished in other ways such as by the creation ofa fog spray which travels generally in parallelism with the inner surface of the conduit and at a velocity such that the minute droplets are flashed into steam without the occurrence ofa film on the inner surface ofthe conduit. It is important to the successful practice of this invention that the water be introduced into the conduit and flashed into steam without the occurrence of any film on the inner surface of the conduit.

The water is sprayed in at a relatively high pressure of the order of 500 to 1,000 psi. and normally is preheated to a temperature of the order of 100 150F. In the region of the entering spray the inner surface of the conduit is maintained at a temperature such that the entering droplets of water are flashed into steam substantially instantaneously. Preferably, the inner surface of the conduit in the region of the spray is maintained at a temperature of the order of l,0OF. Under these conditions the entering droplets when injected into the intensely heated atmosphere in the region of the jet are carried along for a brief instant during which the water flashes into steam and as they do so it is believed that a slight vacuum is created behind them which assist in maintaining them in suspension. As the water is flashed into steam the resulting increase in volume is attended with a pressure build-up which propels the steam toward the open outlet at a very high velocity. When the water is flashed into steam the combination of the injection of the water at high velocity and the propulsion of the steam at high velocity serves to maintain the buoyancy of the impurities entrained in the entering water. in any case, regardless of theory it has been discovered that the energy conditions incident to projecting the water spray at high pressure and the highly heated confining inner surface of the conduit result in the creation of a velocity at which the inner surface of the conduit is self-scavenging in that the entrained impurities do not become deposited thereon. At the same time the entrained impurities become highly heated by taking up heat which is carried with them and which during a later portion of the travel by partial surrender thereof assist in maintaining the thermal energy level of the superheated steam.

After the flashing of the injected water into steam occurs the conditions of confinement within the highly heated inner surface of the conduit are maintained and the steam substantially immediately after its formation, namely, in only about 2 or 3 seconds, becomes superheated while being propelled at very .high velocity as the result of the translation of the heat energy into superheat and kinetic energy. It has been further discovered, according to this invention, that the velocity level is attained or exceeded at which the inner surface of the conduit is self-scavenging in that there is no deposit or other adverse effect due to the impurities contained in the entering water.

While this invention is not to be regarded as dependent upon any theory that is mentioned herein, it is believed that when steam is travelling through a conduit under conventional conditions there is a fllm immediately adjacent the inner surface ofthe conduit that is relatively stagnant. When this is the case the steam travelling through the conduit is heated by the heated inner surface of the conduit partly by conduction through the relatively stagnant film and partly by convection after the heat energy has passed through the film. So long as the film is present in substantial thickness in contact with the heated inner surface of the conduit any impurities contained in the water tend to deposit on or otherwise attack the inner surface of the conduit. However, upon intensification of the conditions which produce velocity a velocity level is reached at which the stagnant layer is substantially eliminated and the travelling steam becomes heated virtually entirely by convection from the inner surfaces which remain clean and unaffected notwithstanding continuous operation for an indefinitely long period of time. i

The diameter of the inner surface of the conduit will depend on the rate at which it is desired to produce super-heated steam. The conduit need not be a large one in order to produce large output of superheated steam. Thus, when using a conduit in the form ofa pipe having an internal diameter of 0.834 inch superheatedsteam may be produced at the rate of 5 to 15 pounds per second.

For aconduit having a given size the water is sprayed into it at a rate such that when it is flashed into steam and substantially immediately superheated the resulting velocity of the superheated steam is such as to attain the aforesaid critical level at which the inner surface of the conduit becomes self-scavenging. Moreover, heat is supplied at a rate which converts the water into steam and supplies the superheat as well as the energy which becomes translated into kinetic energy such that the aforesaid critical velocity level is maintained. The only limitation in this regard is that the heat not be in excess of that which the material of the conduit can withstand under operating conditions and so as to provide, as well, an acceptable factor of safety. So long as the supply of water is maintained the walls of the conduit are cooled because of the heat of vaporization of the water as well as the creation of superheat and kinetic energy. However, the heat energy should not be so far in excess of that which is continuously being converted as aforesaid so as to result in raising the temperature of the conduit so high as to be in excess of the safety factor to be maintained. More generally, when practicing this invention the water is injected into the elongated conduit at a rate such that when flashed into steam and the steam is superheated within the conduit the induced velocity will at least attain the velocity at which the conduit is self-scavenging and the heat is supplied with an intensity and to an extent which are effective to produce the desired flashing into steam and attainment of self-scavenging velocity but which is so controlled and adjusted as not to heat the conduit to a temperature in excess of that which is consistent with the desired factor of safety.

The necessary conditions may be readily arrived at. Thus for a conduit of given diameter the rate of introduction of water is increased while at the same time increasing the degree of heat used in heating the conduit so as to cause substantially instantaneous flashing of the water into steam without, however, exceeding the temperature to which the conduit may be safely heated. The size of the conduit which may be used will depend on the capacity that is desired. For ordinary applications the internal diameter of the conduit may be from about one-half inch to about 6 inches. The upper temperature limit at which the conduit wall is maintained is limited solely by the temperature which the conduit wall can safely withstand under operating conditions. In ordinary practice the conduit wall may be maintained at a temperature of the order of 1,000F. to l,lOOF. However, it is to be understood that the foregoing is merely illustrative and that this invention is attained whenever the velocity becomes sufficiently great that the conduit is caused to be self-scavenging.

In ordinary preferred practice the required heat energy is supplied by the flame from a burner and by the resulting hot combustion gases. As a fuel, propane is preferred in combination with pure oxygen or air. Alternatively, natural gas may be used instead of propane.

Producer gas mixed with oxygen also may be used. In

preferred practice the flame temperature is of the order of 5,000F., although lower flame temperatures of the order of 2,600 to 3,000F. may be employed.

The pressure that is built up by the flash formation of steam and followed by superheating it while confined in the conduit propels the steam toward the open outlet of the conduit. Thus in typical preferred practice the steam becomes heated to a temperature of about 950F. and the pressure builds up to about 950 psia under the conditions of confinement provided by the elongated conduit with resultant propulsion of the steam at an extremely high velocity that equals or exceeds the critical self-scavenging velocity as it travels toward the open remote end of the conduit. As it travels toward the open remote end the temperature and pressuremay fall somewhat but so long as the superheated steam is within the conduit the critical selfscavenging velocity is maintained. In ordinary practice the temperature of the steam is maintained in the range from about 500 to about 1,000F. and the pressure is in the range from about 500 to about 1,000 psia. During travel through the conduit theimpurities not only remain entrained with the steam but also become highly heated initially and during the latter portion of their travel through the conduit serve to counteract cooling of the steam by giving up tangible heat to the steam. The increased density of the air which results from the high pressure increases the buoyant effect of the superheated steam on the impurities and assists in maintaining them entrained in the steam.

The foregoing features of the invention may be carried out in different ways. Thus the entire operation may be carried out using a single conduit. However, it is preferred practice of the invention to accomplish the initial flashing into steam together with at least part of.

the superheating in a plurality of conduits in a single combustion chamber or furnace. In this way more intense heating of a given volume of water so as to cause so as to continue to bathe the conduit for the steam passing through the superheater. By way of illustration, the temperature of the flame in the combustion zone of the thermal energy generator may be of the order of 6,000F. but the temperature of the residual hot combustion gases may fall to about 2,.600F. when passing through the superheater.

The thermal energy generator has many uses. For example, it is of great value in connection with secondary oil recovery wherein superheated steam is used to stimulate flow of oil into a producing well as in the practice of the invention disclosed in my U.S. Pat. No.

3,581,821. For such purposes the thermal energy generator has the unique capacity of generating superheated steam using water recovered from the formation at the drilling site or connate water which may range from fresh or brackish water to salty water. The operating unit also has the great advantage of being so small in relation to output capacity that, if desired, it can be mounted on an ordinary truck and can readily be moved from place to place in assembled condition ready to be connected up and used. The generated superheated steam travelling at high velocity also may be used for producing foundations and in thermal shock drilling when utilizing the procedures and apparatus flashing and production of superheated steam can be accomplished rapidly. This portion of the thermal energy generator maybe referred to as the steam generator portion.

It also is preferred in the practice of this invention to continue the supply of superheat in a zone outside the combustion chamber or furnace in which the initial flashing of the water and the generation of superheated steam is caused to occur. This portion of the thermal energy generator is referred to herein as the superheater portion. In this zone the steam continues to travel through a conduit at the high velocity which maintains the conduit self-scavenging. In the superheater hot combustion gases and some flame plasma are directed from the combustion chamber or furnace described in -my U.S. Pat. Nos. 2,858,676 and 3,152,651. The high energy superheated steam may also be used as a power source in the driving of a turbine or ofajet engine as, for example, in the propulsion of ships.

The apparatus that embodies and is employed in the practice of this invention is simple and compact in relation to its output of energy. A combustion chamber is provided wherein flame from a burner envelops and heats the elongated conduit which has a linear portion into which feed water is sprayed in so that the direction of the spray is in substantial alignment therewith. For

greater compactness, the continuation of the linear portion of the conduit is in the form of a coil. The feed water is pumped at high pressure into the unit preferably after having passed through a screen which removes gross particulate contaminants. Means is provided for preheating the feed water and it preferably is in the form of a jacket disposed about the combustion chamber so as to keep the outer casing of the combustion chamber from becoming heated to a temperature in excess of that which the material of the casing may safely withstand. The preheated water then is directed to the spray jet means at the inlet end of the elongated conduit. 1

The output capacity preferably is enhanced bythe employment in the combustion chamber of the steam generator portion of a plurality of elongated conduits into each of which feed water is sprayed from a header I and each of which comprises a coil. In the terminal heating period in the superheater wherein the steam is superheated outside the combustion chamber by the hot combustion gases it is not necessary to continue independently each conduit of a plurality of conduits. Thus each conduit of the plurality of conduits within which the water is initially flashed into steam by suitable means such as a header may be'caused to feed into a single conduit which, while of larger diameter, is dimensioned so that the superheated steam continues to travel at a velocity at which the inner surface of the conduit is self-scavenging. By directing the hot combustion gas and residual flame plasma so as to bathe the conduit the steam becomes further superheated as hereinabove described.

It is to be understood that reference is made herein and in the claims to the injection of feed water into the inlet of an elongated conduit having an inlet end and an open outlet remote from the inlet whether or not the conduit may be one of a plurality of conduits which merge together prior to the open outlet. It also is to be understood that the open outlet may be close to the region of heating or may be removed therefrom. Thus the conduit may be continued into a drilled oil well or may be continued into operational relation with the blade of a turbine for continuous discharge through the open mouth of the conduit.

When reference is made herein and in the claims to impure water the reference is to water having a content of impurities that in ordinary engineering practice would be regarded as in excess of that which may be used in conventional steam generating equipment. The water may or may not be potable, for potable water as supplied by most municipal water supply systems andwells contains a certain amount of hardness such as that occasioned by dissolved calcium and magnesium salts and dissolved oxygen. Such impurities even in water that is potable are injurious if included in the feed water of a conventional steam generator due to scaling or attack on the boiler tubes or other heating surfaces. However, as stated hereinabove, it is an important advantage of this invention that water may be used which is so impure as not to be potable and Which contains impurities far in excess of those contained in potable water. In fact, the pressure of a substantial quantity of impurities is beneficial to operation in that the impurities act as vehicles for sensible heat so as to assist in the maintenance of the energy level as the superheated steam travels through the conduit. Any impurities which pass the spray nozzle which sprays the water into the conduit can be accommodated. The only precaution that need be taken is that of preliminary screening to screen out solid debris which would not pass the spray nozzle. Under ordinary conditions there is no upper limit as regards the impurity content of the feed water. However, in the case of concentrated solutions such as saline solution at concentrations of the order of 20 percent or more care advisedly should be taken to try out such a solution before setting up an operation ofintended long duration.

BRIEF DESCRIPTION OF THE DRAWINGS Further objects, features and advantages of this invention will be apparent from the following description of this invention in connection with the specific embodiment thereof that is shown merely by way of example in the accompanying drawings, wherein:

FIG. 1 is a diagrammatic showing of apparatus comprising the thermal energy generator of this invention and associated apparatus;

FIG. 2 is a side elevation partly in section of the thermal energy generator;

FIG. 3 is a plan view of the elongated conduit means within the combustion chamber of the thermal energy generator;

FIG. 4 is an end elevation of the elongated conduit means taken on the line 4-4 of FIG. 3;

FIG. 5 is an end elevation of the conduit means taken on the line 55 of FIG. 3;

FIG. 6 is a detail plan view of the steam header for receiving steam from the elongated conduit means disposed in the combustion chamber;

FIG. 7 is a detail plan view showing the spray jet means at the inlet end of each of three elongated conduits and a header for supplying same;

FIG. 8 is a sectional elevation taken on the line 88 of FIG. 2;

FIG. 9 is a sectional elevation taken on the line 99 of FIG. 2; 7

FIG. 10 is a perspective view of the superheater portion of the thermal energy generator;

FIG. 11 is a cross-section on the line lll1 of FIG. 10; and 4 FIG. 12 is a schematic representation of the phenomena taking place when the water is injected into the elongated conduit within the combustion chamber and which also takes place in the conduit within the superheater.

DETAILED DESCRIPTION OF APPARATUS Having reference more especially to FIGS. 1 and 2, the steam generator portion of the thermal energy generator is indicated generally by the reference character 20. The apparatus as shown in FIG. 1 is illustrative of that which is suitable for a complete mobile unit such as a truck.

Fuel such as diesel oil or gasoline is contained in the fuel tank 21 from which it is taken by line 22 containing the filter 23 controlled by valve 24 to the engine 25 which supplies power for the generator 26 for supplying electric power. If desired, the fuel for the engine 25 may be continuously recycled to the fuel tank 21 through the return line 27 controlled by the valve 28.

The electric generator 26 by line 29 supplies electric power to the motor 30 which drives the pump 31 through power shaft 32. The. pump 31 is supplied with water through the inlet line 33 which contains the filter screen 34 the function of which is to screen out gross particulate impurities which may be present in the water source such as flora, fauna, mineral particles and other debris. As aforesaid, the water source may be any that is conveniently available regardless of dissolved salt content or other impurities. The pump is a high pressure pump which must be capable of producing the high pressure hereinabove mentioned at which the water is sprayed into the elongated conduit. The water is pumped via line 35 to the header 36 from which the water is fed into the jacket 38 of the steam generator 20 through a plurality of feed-in lines 39. The line 35 contains the valve 40 and the control valve 41 which by known means (not shown) controls the amount of water fed into the steam generator in relation to the heat energy supplied to the combustion chamber so as to guard against either overheating or insufficient heat to accomplish the desired flash vaporization and conversion to superheated steam. The control preferably is responsive to the temperature of the steam that is formed within the conduits into which the water is sprayed for flash conversion into steam.

The line 82 is for the purpose of returning water to the water source whenever the water pressure on the valve 41 exceeds the limit for which it is designed or the limit presented by the control.

The waterjacket 38 is mounted on and surrounds the casing 42. It is provided with internal strengthening ribs 61 which have holes 62 therein to permit flow from compartment to compartment during travel of the water from the header towards the opposite end of the jacket.

The casing 42 at one end has the head 43 secured thereto for mounting the burner gun 44. The other end of the casing 42 has the closure head 45 secured thereto on which is mounted the pressure release safety valve 46. The casing 42 is lined with a layer of refractory material 47. The burner is supplied with fuel from propane tanks 48 and from oxygen tanks 49 through valve-controlled lines 50 and 51, respectively, to the mixing valve 52 from which the combustible mixture is taken to the burner gun 44 by the line 52A. The combustible mixture discharged from the burner gun 44 is ignited by the igniter electrodes 53 which during operation are activated continuously to ignite the combustible mixture by electricity transmitted thereto by conductors 54 and 55.

Within the combustion chamber there are three elongated conduits 56 (FIGS. 2 and 3) each of which has a linear portion 56A that is. secured to a spray nozzle 57 and that extends longitudinally with respect to the axis of the casing 42. The spray nozzles 57 in turn are secured to the water header 58 into which water from the jacket 38 is directed, by line 59 controlled by valve 60 (FIGS. 7 and 9).

The linear portion 56A of each of the elongated conduits is followed by a coiled portion as shown in FIGS.

The gases may then be directed from the header 68 through the conduit 74 to the outlet 75 through the hot gases are bled off. The conduit 69 is maintained in desired concentric spaced relation with respect to conduit 73 by supports 76 and the'conduit 70 is maintained in desired concentric spaced relation with respect to conduit 74 by supports 77 as shown in FIG. 11. If desired, the hot gases may be bled from the header 68 by the outlet 78. The outlets 75 and 78 are provided with means 79 and 80, respectively, for varying the rate of flow therethrough. In the superheater the steam travelling through lines 69 and 70 are bathed with the hot gases and flame plasma travelling through conduits 73 and 74, respectively, and the steam becomes further superheated. The degree of superheat can be con trolled by varying the amount of hot combustion gases discharged through outlet 78 in relation to outlet 75. Further control can be had, if desired, by directing part of the hot combustion gases directly to conduit 74 through branch line 87 as illustrated in FIG. 1.

EXAMPLE The following is a typical example of the practice of this invention utilizing the preferred apparatus described hereinabove in connection with the drawings.

Each of the three elongated conduits in the combustion chamber of the thermal energy generator is ap- 2 and 3, which coiled portion is brought back so as to become terminated by the connections 63 at the header 64 which directs the steam into the steam line 65 that preferably contains the flexible portion 66. The

header 64, the steam line 65 and the flexible portion thereof 66 are of such size as to accommodate the steam discharged from the three elongated conduits 56 and maintain the velocity of the steam passing therethrough at or above the level at which the inner surfaces are self-scavenging.

The steam line directs steam from the steam generator 20 to the superheater portion of the system which preferably supplements the steam generator and adds further superheat to the steam. The superheater is indicated generally by the reference character 67. In the embodiment shown it is in the form of two sets of concentric conduits connected in sequence by the header 68. The inner conduit 69 of one of these sets is a continuation of the steam line 65 and is connected to the inner conduit 70 of the other set by the U" connection.

71. In the embodiment shown the inner conduit 70 is shown as directing the superheated steam out of the system. The line 70 may be continued, for example, so as to direct the superheated steam into an oil well or into an engine. If it is desired to temporarily discharge the steam into the atmosphere the valve 79 in blowdown line 80 may be opened followed by closing the valve 81 in line 70.

The products of combustion are highly heated in the combustion chamber or furnace of the steam generator and these gases while commingled with residual flame plasma are directed from the combustion chamber by the line 72 which contains the flexible portion 72A to the outer conduit 73 and thence into the header 68.

proximately 33 feet in length and has an inner diameter of 0.834 inch. Any alloy having the requisite strength and heat-resistance may be employed such as an ironnickel alloy or monel. The length of the linear portion into which the water spray is injected is about 7 feet. impure water from any convenient source after screening out gross particulate matter is brought to a pressure of I50 psia by the pump 31 and the spray nozzle is of such design that under said pressure the water is sprayed into the elongated conduit at the rate of 5 lbs. per second in the form of a cone, the outermost particles of which travel in a direction that is at an angle of only about 1 to 2 with respect to the inner surface of the conduit. A mixture consisting essentially of 1 part propane and 3.67 parts pure oxygen is, fed into and through the burner while continuously actuating the igniters 53 to produce a flame at a temperature of about 5,000F. and at a rate such that the wall of the conduit is maintained at a temperature of about l,O0OF. As aforesaid, under optimum operating conditions the steam becomes heated to a temperature of about 950F. and the pressure becomes built up to about 950 psia. The steam passes from the three conduits in which it is initially formed into the superheater wherein the temperature of the steam is maintained at about l,000F. in passing through the conduit comprised in the superheater which is bathed with hot combustion gases and residual flame plasma at a. temperature of about 2,600 to 3,000F. Superheated steam at a temperature of about 950F. and at a pressure of about 950 psia is discharged through the outlet conduit, the energy output resulting from the water input of 5 lbs. per second being about 1,478 BTU per lb. Such operating conditions may be maintained continuously for as long as desired. In order to facilitate control of the operating conditions a pressure gauge 88 andathermometer 89 may be employed to measure the pressure and temperature, respectively, of the superheated steam as it leaves the furnace portion of the thermal energy generator and a measure gauge 90 and thermometer 91 may be employed to measure the pressure and temperature, respectively, of the superheated steam as it leaves the superheater.

While this invention is not to be regarded as dependent on any theoretical considerations expressed herein, nevertheless some of the phenomena which take place are believed to occur in the manner illustrated in FIG. 12. The spray nozzle 57 projects the incoming preheated water at high velocity in the form of a cone without immediately touching the highly heated inner surface of the conduit 56. Proximity to this highly heated surface causes the water particles to flash into steam while at the same time creating a vacuum behind them which assists in maintaining the buoyancy of the incoming spray. To the extent that any of the particles come into contact with the inner surface of the conduit, they do so at a small angle concomitantly with the virtually instantaneous creation of high pressure and high velocity which effectively carries the entrained impurities along without deposit or other prejudicial effect on the inner surface of the conduit. As the steam travels into and through the superheater along with the impurities entrained therein, the particulate impurities having initially become highly heated will now lose some heat to the steam and assist in maintaining its superheat.

The foregoing description has application to continuous operation. In order to start up, the conduits in which steam is produced initially may be filled with water or may be saturated with water until water appears downstream from the superheater. The flame is then turned on and the feed water is slackened off but not shut off. When steam first appears downstream from the superheater, the feed water is increased until the desired balance is obtained for continuous operation as hereinabove described. The regulation may be accomplished by manual control. However, the thermal energy generator lends itself readily to automatic control of known type that is responsive to temperature and pressure.

Another procedure for starting up is to turn on the flame and feed water at the same time and balance one against the other until the desired steam temperature and pressure are obtained.

The method and apparatus of this invention are primarily intended for continuous operation over a relatively long period of time. If the generator is shut down the conduits in which the steam is formed and carried should immediately be flushed out with a substance adapted to remove any entrained chemicals which may settle out of any residual water and condensate. For this purpose the valve 84 in line 33 is closed and the valve 85 in flush line 86 is opened so as to admit a flushing solution from a suitable source and pump it through the steam conduits. For this purpose a suitable solution may be used which consists, for example, of a commercial hard water detergent mixed with water.

The thermal energy generator exemplified hereinabove while capable of producing pounds of superheated steam per second may be constructed so as to be only about 7 feet in overall length. As aforesaid, it and the apparatus associated therewith may easily be carried on a mobile unit such as a conventional truck. Of course, the thermal energy generator may also be made in other sizes depending on the output that is desired.

While this invention has been described in connection with certain specific embodiments thereof, it is to be understood that this has been done merely for the purpose of illustration-and that the invention may be variously applied and utilized in accordance with its rationale as hereinabove set forth.

lclaim:

l. A method of producing superheated steam which comprises continuously spraying impure water into the inlet end of an elongated conduit having an inlet adjacent one end and an open outlet remote from said inlet, maintaining the inner surface of said conduit at a temperature at which the injected water is continuously and virtually instantaneously flashed into steam within said conduit and at which the steam under the confinement imposed by said inner surface of said conduit becomes rapidly converted into superheated steam concomitantly with build-up of pressure which propels the steam through the conduit toward said outlet at a velocity which is at least the velocity at which the inner surface of the conduit is self-scavenging, and continuously discharging from said outlet superheated steam having entrained therewith the impurities contained in the water sprayed into said conduit.

2. A method according to claim 1 wherein the flashing intosteam and propulsion of superheated steam.

through said conduit is carried out at a rate which eliminates the occurrence of a liquid film on the interior surface of the conduit.

3. A method according to claim 1 wherein said conduit in the portion thereof at which the sprayed water occurs is substantially linear and wherein the water is sprayed into the conduit so that the direction of the sprayed water is in substantial alignment with said linear portion of said conduit.

4. A method according to claim 3 wherein the direction of travel of none of the particles of the sprayed water is at an angle greater than about 4 with respect to the inner surface of said linear portion of the conduit.

5. A method according to claim 4 wherein the water is sprayed into said conduit at a pressure of at least about 500 psia.

6. A method according to claim 5 wherein said water is preheated to a temperature of at least about F.

7. A method according to claim 3 wherein the elongated conduit is comprised of thermally conductive material and the interior surface thereof is heated by the application to the exterior of the conduit flame and hot products of combustion which are at a temperature of about 2,600F. to about 6,000F.

8. A method according to claim 3 wherein the water spray is flashed into steam at a temperature of at least about 500F. with concomitant build-up of pressure to at least about 500 psia.

9. A method according to claim 2 wherein sensible heat initially imparted to impurities entrained in the steam is utilized in maintaining the energy level of the superheated steam during the latter portion of its travelthrough the conduit.

10. Apparatus for producing superheated steam comprising an elongated conduit which has an inlet end and an outlet remote from said inlet end, jet spray means for injecting water into said conduit at said inlet end, water supply means for supplying water under pressure to said'spray jet means, said conduit having a linear portion in the region where said spray occurs and said spray jet means being adapted and disposed for spraying water into said conduit with the direction of said spray substantially in alignment with said linear portion of the conduit and at a rate sufficiently great to build up pressure in said conduit in the region of said spray upon conversion of the water into steam, and heating'means adapted and arranged to maintain said conduit at a temperature at which the sprayed water is flashed into steam and the resulting steam is super heated within the conduit while travelling toward said outlet propelled by said pressure build-up.

11. Apparatus according to claim 10 wherein said water supply means comprises a pump which pumps water to said 'spray jet means at a pressure of at least about 100 psia and wherein said spray jet means sprays water into the linear portion of the conduit so that none of the particles of the spray travel at an angle greater than about 4 with respect to the inner surface of the conduit.

12. Apparatus according to claim 11 which includes preheating means for heating water prior to being sprayed into said elongated conduit.

13. Apparatus according to claim 10 wherein said heating means comprises a combustion chamber which surrounds said elongated conduit in the region thereof wherein the water sprayed from said spray jet means is converted into steam and into superheated steam and burner means which is adapted to provide flame and hot products of combustion within said combustion chamber which envelop said region of said elongated conduit, said combustion chamber having an outlet for discharge of products of combustion 14. Apparatus according to claim 13 which c0mprises a water preheating chamber disposed about said furnace chamber adapted to heat water contained therein by heat transmitted through the wall of said furnace chamber and means comprised in said water supply means for directing water through said water preheating chamber and then to said spray jet means for being sprayed into said conduit.

15. Apparatus according to claim 13 wherein a portion of said conduit terminated by said outlet extends beyond said combustion chamber and which comprises a jacket which surrounds said conduit between said combustion chamber and said outlet and means for directing hot products of combustion from said combustion chamber through said jacket in contact with the peripheral surface of said conduit.

16. Apparatus according to claim 15 wherein there is a plurality of elongated conduits within the combustion chamber into which water is sprayed by said spray jet means, a header into which each conduit of said plurality of conduits feeds steam, and wherein said header discharges into a single conduit which is surrounded by said jacket and which constitutes a common continuation of each of the conduits within the combustio chamber. I

17. Apparatus according to claim 10 which includes 

1. A method of producing superheated steam which comprises continuously spraying impure water into the inlet end of an elongated conduit having an inlet adjacent one end and an open outlet remote from said inlet, maintaining the inner surface of said conduit at a temperature at which the injected water is continuously and virtually instantaneously flashed into steam within said conduit and at which the steam under the confinement imposed by said inner surface of said conduit becomes rapidly converted into superheated steam concomitantly with build-up of pressure which propels the steam through the conduit toward said outlet at a velocity which is at least the velocity at which the inner surface of the conduit is self-scavenging, and continuously discharging from said outlet superheated steam having entrained therewith the impurities contained in the water sprayed into said conduit.
 2. A method according to claim 1 wherein the flashing into steam and propulsion of superheated steam through said conduit is carried out at a rate which eliminates the occurrence of a liquid film on the interior surface of the conduit.
 3. A method according to claim 1 wherein said conduit in the portIon thereof at which the sprayed water occurs is substantially linear and wherein the water is sprayed into the conduit so that the direction of the sprayed water is in substantial alignment with said linear portion of said conduit.
 4. A method according to claim 3 wherein the direction of travel of none of the particles of the sprayed water is at an angle greater than about 4* with respect to the inner surface of said linear portion of the conduit.
 5. A method according to claim 4 wherein the water is sprayed into said conduit at a pressure of at least about 500 psia.
 6. A method according to claim 5 wherein said water is preheated to a temperature of at least about 100*F.
 7. A method according to claim 3 wherein the elongated conduit is comprised of thermally conductive material and the interior surface thereof is heated by the application to the exterior of the conduit flame and hot products of combustion which are at a temperature of about 2,600*F. to about 6,000*F.
 8. A method according to claim 3 wherein the water spray is flashed into steam at a temperature of at least about 500*F. with concomitant build-up of pressure to at least about 500 psia.
 9. A method according to claim 2 wherein sensible heat initially imparted to impurities entrained in the steam is utilized in maintaining the energy level of the superheated steam during the latter portion of its travel through the conduit.
 10. Apparatus for producing superheated steam comprising an elongated conduit which has an inlet end and an outlet remote from said inlet end, jet spray means for injecting water into said conduit at said inlet end, water supply means for supplying water under pressure to said spray jet means, said conduit having a linear portion in the region where said spray occurs and said spray jet means being adapted and disposed for spraying water into said conduit with the direction of said spray substantially in alignment with said linear portion of the conduit and at a rate sufficiently great to build up pressure in said conduit in the region of said spray upon conversion of the water into steam, and heating means adapted and arranged to maintain said conduit at a temperature at which the sprayed water is flashed into steam and the resulting steam is superheated within the conduit while travelling toward said outlet propelled by said pressure build-up.
 11. Apparatus according to claim 10 wherein said water supply means comprises a pump which pumps water to said spray jet means at a pressure of at least about 100 psia and wherein said spray jet means sprays water into the linear portion of the conduit so that none of the particles of the spray travel at an angle greater than about 4* with respect to the inner surface of the conduit.
 12. Apparatus according to claim 11 which includes preheating means for heating water prior to being sprayed into said elongated conduit.
 13. Apparatus according to claim 10 wherein said heating means comprises a combustion chamber which surrounds said elongated conduit in the region thereof wherein the water sprayed from said spray jet means is converted into steam and into superheated steam and burner means which is adapted to provide flame and hot products of combustion within said combustion chamber which envelop said region of said elongated conduit, said combustion chamber having an outlet for discharge of products of combustion.
 14. Apparatus according to claim 13 which comprises a water preheating chamber disposed about said furnace chamber adapted to heat water contained therein by heat transmitted through the wall of said furnace chamber and means comprised in said water supply means for directing water through said water preheating chamber and then to said spray jet means for being sprayed into said conduit.
 15. Apparatus according to claim 13 wherein a portion of said conduit terminated by said outlet extends beyond said combustion chamber and Which comprises a jacket which surrounds said conduit between said combustion chamber and said outlet and means for directing hot products of combustion from said combustion chamber through said jacket in contact with the peripheral surface of said conduit.
 16. Apparatus according to claim 15 wherein there is a plurality of elongated conduits within the combustion chamber into which water is sprayed by said spray jet means, a header into which each conduit of said plurality of conduits feeds steam, and wherein said header discharges into a single conduit which is surrounded by said jacket and which constitutes a common continuation of each of the conduits within the combustion chamber.
 17. Apparatus according to claim 10 which includes means for shutting off water supplied to said spray jet means by said water supply means, and means for supplying a cleansing solution to said spray jet means when said water supply means is shut off. 